package com.qixiucoding.context;

import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;

/**
 * @Author longhj
 * @Description TODO
 * @Date 2021/10/04 星期一 10:47
 */
@Component
public class AppContext implements ApplicationContextAware {


    private static ApplicationContext context = null;

    /**
     * 实现ApplicationContextAware接口的context注入函数, 将其存入静态变量
     */

    @Override
    public void setApplicationContext(ApplicationContext context) {
        AppContext.setContext(context);

    }

    /**
     * 取得存储在静态变量中的ApplicationContext.
     */
    public static ApplicationContext getContext() {

        if (context == null) {
            throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义AppContext");
        }
        return context;

    }

    /**
     * 存储静态变量中的ApplicationContext.
     */
    public static void setContext(ApplicationContext context) {
        AppContext.context = context;
    }

    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型
     */

    @SuppressWarnings("unchecked")
    public static <T> T getBean(String name) {
        if (context == null) {
            throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义AppContext");
        }
        try {
            return (T) context.getBean(name);
        } catch (BeansException e) {
            e.printStackTrace();
        }
        return (T) null;
    }


    /**
     * 从静态变量ApplicationContext中取得Bean, 自动转型为所赋值对象的类型
     */
    @SuppressWarnings("unchecked")
    public static <T> T getBean(Class<T> tClass) {
        if (context == null) {
            throw new IllegalStateException("applicaitonContext未注入,请在applicationContext.xml中定义AppContext");
        }
        try {
            return context.getBean(tClass);
        } catch (BeansException e) {
            e.printStackTrace();
        }
        return null;
    }
}

